Oxygen Sensor: Service and Repair

HO2S REPLACEMENT

TOOLS REQUIRED

J 39194 Oxygen Sensor Wrench.

NOTE: The Heated Oxygen Sensors each use a permanently attached pigtail and connector. This pigtail should not be removed from the heated oxygen sensor. Damage or removal of the pigtail or connector could affect proper operation of the heated oxygen sensor.

REMOVAL PROCEDURE

IMPORTANT:
^ Use care when handling the heated oxygen sensor. The in-line electrical connector and the louvered end must be kept free of grease, dirt, or other contaminants. Also, avoid using cleaning solvents of any type. DO NOT drop or roughly handle the heated oxygen sensor/catalyst monitor. A dropped sensor will not operate properly.
^ The heated oxygen sensor may be difficult to remove when the engine temperature is below 48°C (120°F). Use of excessive force may damage the threads in the exhaust manifold or the exhaust pipe.

CAUTION: Refer to Battery Disconnect Caution in Service Precautions.

1. Disconnect the negative battery cable.
2. If the heated oxygen sensor 2 (HO2S 2) is being replaced, raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.




3. Disconnect the HO2S electrical connector.
4. Use the J 39194 oxygen sensor wrench in order to carefully back the HO2S out of the exhaust.

INSTALLATION PROCEDURE





IMPORTANT: A special anti-seize compound is used on the heated oxygen sensor threads. The compound consists of graphite suspended in fluid and glass beads. The graphite burns away, but the glass beads remain, making the sensor easier to remove. New or service sensors already have the compound applied to the threads. If a sensor is removed from an engine and is to be reinstalled, the threads must have anti-seize compound applied before reinstallation.

1. Coat the threads of the heated oxygen sensor/catalyst monitor with anti-seize compound GM P/N 5613695, or equivalent, if necessary.





NOTE: Refer to Fastener Notice in Service Precautions.

2. Use the J 39194 oxygen sensor wrench in order to install the HO2S.

Tighten
Tighten the HO2S to 41 N.m (30 lb ft).

3. Connect the HO2S sensor electrical connector.
4. Connect the negative battery cable.